In the distant past when farming was still in its infancy, little was done to a crop in the way of adding artificial growth stimuli. Even the simplest form of fertilizer (decaying organic matter) was not fully appreciated as an additive to increase yield.
As time passed, both population and land value increased. Therefore, simple economics dictated that a farmer had to somehow realize a greater yield per acre of land.
Science began to appreciate the needs of the agricultural world and began to investigate the entire spectrum of problems that had to be solved. First among these problems to be understood was the importance of fertilizer. Therefore, new and better fertilizers were developed for customized application to different crops. Next was the development of hybrids which were disease resistant and could withstand a greater range of weather conditions. In addition, other fields of endeavors were entered upon. They included weather forecasting, seed production, crop rotation, irrigation systems, pest control, weed control and many other pertinent areas.
Recently, in the areas of weed and pest control, much research has been undertaken with outstanding results being obtained. Herbicides and pesticides have been developed that virtually eliminate any and all weeds and pests. But, research goes on because newer and more effective chemicals are needed to replace those which become ineffective.
However beneficial these chemicals might be, not until recently has much been done to evaluate the adverse effects that various herbicides and pesticides have had on the environment. For example, DDT was a widely used pesticide that was found to retain its chemical composition for extended periods. The result being that it has lingered in the environment and produced harmful side effects on wildlife. Its use has since been halted. Other chemicals have been found to possess a very long active life thus creating and extending period of contaminating the environment.
The Environmental Protection Agency has been created by the federal government to monitor environmental changes and determine the causes of the same. In addition, this agency evaluates various consumer products, especially those that pertain to food and water, and removes such products from the market which are deemed harmful. Therefore, companies are now careful to put on the shelf only those products which they feel meet the guidelines drawn up by EPA.
It follows that before a company goes into full scale production of a particular product, it is going to test the product for any harmful side effects. It would be foolhardy to go through the expense of advertising and setting up distribution channels if the product could not be sold.
Different products require different types of tests. In the area of pesticides and herbicides it is considered very important to determine the leaching characteristics of each chemical in question. The reason for this being that each chemical has a different rate of being absorbed or leaching through soil and subsequently being deposited in the water table located below the ground. It is very important that the chemical does not leach down to this water table before its chemical composition has broken down. Therefore, tests were developed to simulate in a small scale what would occur in fields where the particular chemical was dispersed. As of the recent past the testing apparatus used is not common to all concerned parties. The outcome being that test results of identical chemicals may vary widely from one laboratory to the next.
Some laboratories have adapted a soda straw type leaching column as a testing device. When such a method is used the column is filled with soil to simulate a core sample. The chemical is then added to the top surface and caused to leach through when water is added. Any leachate which seeps through is collected at the lower end of the column and tested for the presence of the particular chemical. It follows that inconsistent results develop because each company has different control parameters such as various sized columns. Another undesirable feature of the soda straw type column is that it allows the water suspended chemical to flow down the interior walls of the column. Therefore, many times the leachate appears substantially more potent than the EPA would allow. There have even been instances where effective and reliable pesticides and herbicides have not been put on the market because of this inaccurate and non-standardized testing procedure.